Immunofluorescence assay for the detection of antibodies using recombinant antigens in insoluble form

ABSTRACT

The present invention relates to the use of insoluble forms of recombinant proteins in a flow cytometric immunofluorescence assay for the detection of given antibodies.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No. 08/164,789, filed Dec. 10, 1993, now abandoned the content of which is entirely incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an assay for the detection of various disease states which utilizes antigens in insoluble form and more particularly, for the detection of HIV infection. The assay of the present invention has a high sensitivity allowing for detection of antibodies to the HIV virus in the "window" period.

BACKGROUND OF THE INVENTION

Enzyme immunoassays (EIA) and Western Blot assays (WB) have been routinely used for detecting HIV infection for several years. The implementation of these tests has significantly reduced the risk of transfusion-related HIV infection. However, some recent studies based on the detection of HIV DNA have demonstrated that some HIV infected individuals do not have any detectable amount of anti-HIV antibodies when the approved tests are performed. Data from several studies indicate that there is a "window period" estimated to span from a few weeks to several months or even several years between initial HIV infection and seroconversion. Cases of post-transfusion HIV infection have been reported from seronegative blood donors. This is assumed to be a consequence of donation during the "window" period on the part of these donors.

To verify the presence of HIV-antibody in donors of reactive samples to EIA, the Western Blot assay has been used for confirmatory testings (Ulstrup, J. C. et al, Lancet i:1151-1152). In this assay, 6 to 9 characteristic bands indicating antibodies to HIV surface and core antigens are observed if antibodies to HIV-1 proteins are present (positive), and no bands if antibodies are absent (negative). However, a significant proportion of EIA repeatedly reactive samples react only to the HIV-1 gag-derived core proteins (p17, p24 and p55) on the WB test (Kleinman, S., 1990, Arch. Pathol. Lab. Med. 114:298-303, Tribe D. E. et al, 1988, J. Clin. Microbiol. 26:641-647). This reactivity does not meet the definition of HIV-1 positive or negative in the criteria for WB tests and as a result these samples are labelled as HIV-1 WB indeterminates. Studies have established that 30 to 40 percent of EIA repeatedly positive donors are HIV-1 WB indeterminates, a figure that is typical in North America. Follow-up studies performed in regions of high prevalence of HIV show that while 95 to 99 percent of these are not infected with HIV, the remaining 1 to 5 percent of blood donors with HIV-1 WB indeterminate results are true seroconverters, usually at an early stage of infection (Busch, M. P. et al., 1991, Transfusion 31:129-137; Gallo D. et al, 1986, J. Clin. Microbiol. 23:1049-1051). In order to optimize the safety of transfusion, all donors with HIV-1 WB indeterminate results are deferred. The majority of donors with HIV-1 WB indeterminate results undergo needless anxiety, their deferral represents a significant loss of donors and recipients are still worried about contamination of blood taken from "window" period of seroconversion donors. A highly sensitive assay is thus also desirable in order to properly classify these indeterminate results.

Partially purified disrupted virus is used as an antigen for most currently licensed screening and confirmatory tests. Human cells are always used for culturing the HIV-1 virus (Dodd, R. Y. and C. T. Fang, 1990, Arch. Pathol. Lab. Med. 114:240-245). Recombinant proteins and synthetic peptides have been recently licensed for screening tests (Busch M. P. et al., 1991, Transfusion 31:129-137; Das P.C. et al., 1992, Trans Med 2:249-250; Ramirez E. P., 1992, J. Clin. Microbiol. 30:801-805). In theory, these antigens can provide more sensitive and definitive assays. However, most recombinant proteins are produced in E. coli and denatured during the purification and processing of the antigens. Also, a certain proportion of donors still show cross-reactivity to HIV core antigens (such as antigen p24), and sensitivity is limited to detecting very early HIV antibodies.

A serious drawback to the use of synthetic peptides is related to the fact that in some HIV-1 infected patients and seroconverters in high risk populations, the serum antibody titre is very low, or undetectable, either because of complex formation between p24 and antibodies or the loss of specific clones of antibody producing cells (Orsknov, L. B., Eur. J. Clin. Microbiol. Inf. Dis. 8:614). Synthetic peptides, which in general only cover one or two epitopes, do not efficiently detect such low titre antibodies and furthermore have a limited ability to take on the natural three dimensional structures of antigen.

An immunofluorescence assay (IFA) has recently been licensed as an alternate confirmatory test for detecting HIV-1 antibodies (FDA Memorandum, 1992, Summer:56-67). IFA is rapid, simple and inexpensive. However, it is a subjective procedure requiring well trained personnel (Ascher, M. S. 1990, Arch. Pathol. Lab. Med. 114:246-248). This is a limitation for users and false positive and false negative results still occur in the IFA tests because of cross-reactivity of some antibodies to antigens on the human cells in which the HIV virus is cultured. Fixing of the infected cells before incubation also has been shown to lead to false positive and negative results (McHugh, T. M., 1986, Diagnos. Immunol. 4:233-240).

An assay based on immunofluorescence was recently developed to detect antibodies to HIV-1 by using flow cytometry (FIFA) (Sligh, J. M., 1989, Am. J. Clin. Path. 91:210-214). FIFA is a sensitive, quantitative test. In a typical FIFA protocol, HIV-1 infected cells are used directly for the test. However, false positive and false negative results may occur because of the HIV-1 antibody cross-reactivity to the antigens (such as HLA) on human cells in which the virus is cultured and used as antigens in FIFA. Another concern is with biohazards caused by the infectious virus which is a big limitation for users. Fixing the HIV-1 infected cells for inactivation of the virus before incubation has shown to lead to higher cross reactivity on the cells.

The present invention is directed to a flow cytometric immunofluorescence assay (r-FIFA) using insoluble forms of recombinant proteins expressed in an expression system such as the baculovirus system. In a preferred embodiment, r-FIFA is used for the detection of the HIV virus infection. Insoluble forms of recombinant HIV-1 proteins such as HIV-1 gag p45 protein, gag gp-41 chimeric proteins, HIV-1 precursor polyproteins pol 97 and gp160 are used as autologous carriers (in place of beads) and antigens to detect HIV-1 antibodies using flow cytometry. The baculovirus expression system has become a major recombinant protein production system because of several advantages over bacterial and mammalian systems including superior yield of recombinant protein, safety (baculovirus is not infectious to humans) and fidelity of its products.

In sensitivity comparison between r-FIFA and currently licensed tests, r-FIFA was found to be more sensitive, the average increase in sensivity for early detection of HIV-1 infection being greater than 20 days. r-FIFA has permitted the detection and quantification of HIV-1 specific IgG, IgM and IgA antibodies during the window period. The use of HIV-1 recombinant proteins in an immunofluorescence assay (r-FIFA) solves the problems of antibody cross-reactivity to antigen on human cells and the biohazard concern with the original FIFA.

SUMMARY OF THE INVENTION

In a broad embodiment, the invention relates to the use of an insoluble form of at least one recombinant protein as a carrier and antigen in a flow cytometric immunofluorescence assay for the detection of a disease state wherein said protein reacts with an antibody present in said disease state. In a preferred embodiment, the invention relates to the use of an insoluble form of at least one recombinant protein as a carrier and antigen in a flow cytometric immunofluorescence assay for the detection of HIV.

BRIEF DESCRIPTION OF THE DRAWINGS

The file of this patent contains at least one drawing executed in color. Copies of this patent with color drawing(s) will be provided by the Patent and Trademark Office upon request and payment of the necessary fee.

The invention will be better understood through the following detailed description of the preferred embodiment in conjunction with the accompanying drawings in which:

FIGS. 1A-1C represent the construction of a recombinant baculovirus containing the HIV-1 gag gene sequence coding for gag-45 protein. The gag-45 coding region was isolated from the plasmid pHxB-2D (8). FIG. 1A; a Cla1-Bgl II fragment was modified and subcloned into pUC19 by ligation with two synthetic oligonucleotide linkers. FIG. 1B; the linker 1 (SEQ ID NOS:9 and 10) contains a Bam H1 site and the missing sequence including the translation initiation codon (ATG) at N-terminal of gag gene. The linker 2 (SEQ ID NOS:11 and 12) creates a translation termination codon (TAA) followed by a Bam H1 site. FIG. 1C; the Bam H1 fragment was isolated from the pUC19-gag45 and inserted into the Bam H1 site of transfer vector pAcYM1 (9). The recombinant transfer vector pAcYM1-gag 45 was used for co-transfection of SF9 cells with wild type AcNpV DNA and then the recombinant baculovirus gag45 gene was isolated to express the recombinant protein gag45;

FIGS. 2A and 2B show the nucleotide sequence of HIV-1 gag protein p45 (SEQ ID NO:1);

FIG. 3 is the amino acid sequence of HIV-1 gag protein p-45 (SEQ ID NO:2);

FIG. 4 is a schematic representation of the construction of recombinant HIV-1 gag gp41 proteins. Three gag-gp 41 chimeric proteins were constructed based on the truncated gag precursor p45 gene sequence. The gp41 coding region A (nucleotides 7737-8090), 118 a.a.), B (nucleotides 7923-8264, 114 a.a.) and C (nucleotides 7737-8264, 176 a.a.) were amplified by PCR with primers P₁ (SEQ ID NO:13), P₂ (SEQ ID NO:14), p₃ (SEQ ID NO:15) and p₄ (SEQ ID NO:16) which contain a Bgl II enzyme site at both ends and a stop codon TAA at the 3' end and then inserted respectively into the Bgl II enzyme site at 3' end of gag-p45 coding sequence in the recombinant plasmid pAcYm1 gag p45. The chimeric DNAs were isolated and inserted into the Bam H1 cloning site of AcNPV transfer vector plasmid pVL 1393. The recombinant viruses gag-gp 41A, gag-gp 41B and gag-gp 41C were isolated and purified after co-transfection;

FIG. 5 is the nucleotide sequence (SEQ ID NO:3) and amino acid sequence of chimeric protein A (SEQ ID NO:4);

FIG. 6 is the nucleotide sequence (SEQ ID NO:5) and amino acid sequence of chimeric protein B (SEQ ID NO:6);

FIG. 7 is the nucleotide sequence (SEQ ID NO:7) and amino acid sequence of chimeric protein C (SEQ ID NO:8); and

FIGS. 8A-8D represent the titration of HIV-1 seropositive plasma using gag-p45 as the antigen in r-FIFA. FIG. 8A: a flow cytometric histograms of the seropositive and seronegative plasma are presented showing HIV-1 specific antibody (IgG) positive signal (the line peaks) and the negative signal (solid peak). Each of the two line peaks represent the duplicates of the assay. The heavy overlapping of the duplicates indicates the high reproducibility of r-FIFA. FIG. 8B: The median fluorescence intensity of the HIV-1 positive sample (◯) and the negative sample were plotted () over the dilutions (1:25 to 1:25 600). The median fluorescence intensity ratio of HIV-1 positive sample to HIV-1 negative sample (S/N) is highest at 1:25. C: The dilution of 1:25 was chosen for r-FIFA to detect IgG (FIG. 8C) and IgM (FIG. 8D) antibodies (B-IgG and B-IgM) to HIV-1 in a HIV-1 positive sample by double staining with goat anti-human IgG FITC and IgM R-PE;

FIG. 9 represents early HIV-1 antibodies detection in the samples of BB1 anti-HIV-1 seroconversion panel D by r-FIFA using two different antigens. The flow cytometric histograms show anti-HIV-1 antibody signals in those samples (line peaks) and fluorescence signal (background) of the negative sample as control (solid grey peak);

FIGS. 10A-10C represent detection of early HIV-1 antibodies (IgG and IgM) using r-FIFA in the samples from three individuals (PHL-A, (FIG. 10A), PHL-B, (FIG. 10B), PHL-C (FIG. 10C) who were infected but seronegative in the first bleed (upper row) by recently licensed screening tests. The numbers under IgG and IgM indicate the s/c value of the samples; 1.0 or greater is considered positive;

FIGS. 11A-11H represent antibody response during the window period of HIV-1 infection. In this kinetic analysis of IgM and IgG antibody production the results are expressed by median fluorescence intensity ratio of sample to cut-off (s/c) value (left axis). The broken line represents the antibody s/c value level of 1.0. The s/c value on this line or higher is considered positive. The right axis represents the s/c (s/co) value of HIV-1 antigens. A typical primary immune response was found in panels (FIG. 11A), K (FIG. 11C), D (FIG. 11E) and R (A) (FIG. 11G). The immune response pattern in panels E (FIG. 11B), H (FIG. 11D), P (FIG. 11F) and Q (B) (FIG. 11H) is different from the pattern seen in (FIGS. 11A, 11C, 11E and 11G). IgG is the dominant antibody and remains at low level for a long period. (◯) represents IgM antibody to HIV-1, () represents IgG antibody to HIV-1 and (▾) represents HIV-1 antigen;

FIG. 12 represents the kinetics of the immune response during the window period of HIV-1 infection. The fluorescence histograms of samples in BB1 panel K represent IgG, IgM and IgA antibody production showing the phases of primary response at a very early stage of HIV-1 infection. IgA antibody in samples K1 and K2 are significantly stronger than the negative control, but they are still negative by our criteria because the s/c value is higher for IgA than for IgG;

FIGS. 13A and 13B represent antibody detection using antigen gag-gp41-C (p45-cc, FIG. 13A) and gag-p45 (p45, FIG. 13B) in r-FIFA. FIG. 13A: the sample tested had weak antibodies to HIV-1 core (45) and strong antibodies to gag-gp41 (cc) by Western Blot (IgG only).

FIG. 13B: the antigen gag-p45 (45) and antigen gag-gp41 (cc,B) were visualized by Coomassie blue staining of the polyacrylamide gel. The r-FIFA results (FIGS. 13A and 13B) are shown to be concordant with Western Blot results;

FIGS. 14A-14C represent HIV-1 early antibody (IgG) detection by using the gag-p45 antigen and the antigen chimeric gag-gp41-C (p45-cc) in r-FIFA. The results shown indicate that chimeric antigen gag-gp41-C (p45-cc) detects the antibodies earlier and with a stronger signal than the antigen gag-p45 does during the early stage of HIV-1 infection FIGS. 14A-14C represent data obtained from FIGS. 11C, 11A and 11G, respectively.

FIG. 15 represents antibody response to HIV-1 RT precursor pol97 polyprotein tested by r-FIFA during early HIV-1 infection in the anti-HIV-1 seroconversion performance panel J(BB1). The axises represent the s/co value of HIV-1 antigens (right) and the sample to cut-off ratio (s/c) of antibody to pol97 (left). The broken line represents the antibody s/c value of 1.0; and

FIG. 16 represents the detection of antibodies to HIV-1 gag-p45 particles by indirect immunofluorescence. The HIV-1 antibody bound gag-p45 particles were stained with goat antihuman IgG FITC and IgM RPE conjugates showing the HIV-1 specific antibodies IgG (green fluorescence) and IgM (orange yellow fluorescence).

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to the use of an insoluble recombinant protein in a flow cytometric immunofluorescence assay, hereinafter referred to as r-FIFA, for the detection of antibodies. In the examples that follow, the use of insoluble forms of the HIV-1 gag precursor p55, termed p45 protein, which includes p17, p24 and part of p16 and chimeric particles of gag-gp41 fusion proteins; the gp160 and pol97 proteins for the early detection of HIV as well as the hepatitis B core antigen for the detection of hepatitis B is described.

Recombinant proteins for the present invention are prepared in the baculovirus expression system since the baculovirus expression system has several advantages over bacterial and mammalian systems. These include a superior yield of recombinant protein, safety and fidelity of the products. Glycosylation, myristolyation, proteolytic processing and other post-translational modifications that occur in baculovirus expressed proteins are similar or identical to the native HIV-1 proteins and to HIV-1 proteins derived from mammalian cell culture systems.

When expressed in insect cells, baculovirus encoded rp45 exhibits two molecular forms, an insoluble particle form and a soluble protein. The particle form of gag protein consists of a membrane-enveloped corelike particle released into the medium by budding at the plasma membrane. Both of the two forms of gag rp45 are myristoylated (Mervis, R. J., 1988, J. Virol. 62:3993-4002). HIV-1 gag particle is 100 to 120 nm in diameter. It is a good carrier for inserting immunoreactive domains of other proteins, such as neutralizing epitopes of gp120 by using recombinant DNA techniques, thereby extending the immunoreactivity spectrum of this gag protein.

Standard performance panels obtained from BBI (Boston Biomedica Inc.) were used for the evaluation of r-FIFA. These performance panels are made available to enable manufacturers and users to test and assess their anti-HIV-1 test systems, especially with regard to specificity, reproducibility and sensitivity. BBI provides comprehensive data for comparative analysis. Each set of BBI panels includes 6 to 14 aliquots assembled from a repository of frozen sera or plasma units. An anti-HIV-1 low titer performance panel (PRB-104), anti-HIV-1 seroconversion panels D(PRB 904), E(PRB 905), H(PRB-908), J(PRB 910), K(PRB-911), P(PRB-916), Q(PRB-917), R(PRB-918) and three HIV-1 seroconversion specimens provided by PHL were tested and analyzed by r-FIFA. To confirm the specificity of r-FIFA, 295 plasma or serum samples from random blood donors, 105 Western Blot positive samples and 138 E1A reactive, Western Blot indeterminate samples from The Canadian Red Cross Society, National Testing Laboratory were also tested.

EXAMPLE 1 Construction of Recombinant Baculoviruses for the Expression of HIV-1 Gag p45 and Chimeric gag-gp41 Proteins

Recombinant baculoviruses were constructed to express HIV-1 gag p45 and chimeric gag-gp41 proteins gag-gp41 A, gag-gp41 B and gag-gp41 C. The gag p45 coding region (including intact p17, p24 and part of p16 coding sequences) was isolated from the plasmid pHxB-2D (Ratner et al., 1985, Nature 313, 277-284). A Clal-Bgl II fragment was modified and subcloned into pUC19 by using synthetic oligonucleotide linkers. Linker 1 contains a Bam H1 site and the missing sequence including the translation initiation codon (ATG) at the N-terminal of the gag gene. Linker 2 created a translation termination codon (TAA) followed by a Bam H1 site. The Bam H1 fragment was isolated from pUC19-gag p45 and inserted into the Bam H1 site of transfer vector pAcYM1 as illustrated in FIG. 1. The recombinant plasmid pAcYM1-gag p45 was used for co-transfection of SF9 cells with wild type AcNPV DNA and then the recombinant baculovirus gag-p45 was isolated to express the recombinant protein gag p45. Three gag-gp41 chimeric proteins were constructed and are referred to as gag-gp41 A, gag-gp41 B and gag-gp41 C and represented in schematic form in FIG. 4. The gag coding sequence in the three constructions is the same as gag p45. The gp41 coding sequences A (nucleotides 7737-8090, 118 a.a.), B (nucleotides 7923-8264, 114 a.a), and C (nucleotides 7737-8264 176 a.a.) were inserted respectively at the Bgl II site at the end of the gag-p45 gene. The nucleotide and amino acid sequences of gag-p45 (SEQ ID:1 A and SEQ ID:2 respectively) are provided in FIGS. 2 and 3. The nucleotide and amino acid sequences of the three chimeric proteins are provided in FIGS. 5, 6 and 7 (SEQ ID:3 and 4 for Protein A, SEQ ID:5 and 6 for protein B and SEQ ID:7 and 8 for protein C). The chimeric DNAs were isolated and inserted into the Bam H1 cloning site of transfer vector plasmid pVL 1393 and cotransfection was performed using the BaculoGold system (Pharminogen). Recombinant viruses were isolated as chimeric gag-gp41 A, gag-gp41 B and gag-gp41 C.

Construction of Recombinant HIV-1 Gag/Env Chimeric Proteins

Three gag/env chimeric proteins were constructed and were referred to as chimeric A, B, and C as shown in FIG. 4. The gag DNA sequence in the three proteins was the same. That sequence contained a 5' truncated HIV-1 gag protein (p45) sequence excluding the TAA termination codon. In addition, chimeric A contained 118 a.a. env sequences (nucleotides 7737-8090 SEQ ID:3). Chimeric B contained 114 a.a. env sequences (nucleotides 7923-8264 SEQ ID:5) and chimeric C contained 176 a.a. env sequences (nucleotides 7737-8264 SEQ ID:7). The chimeric DNA was inserted into the Bam H1 restriction site of plasmid pVL1393 and cotransfection was performed using the BaculoGold transfection system. The nucleotide sequences of the three chimeric proteins are provided in FIGS. 5, 6 and 7.

a) Amplification of HIV-1 env Regions

About 100 ng of HIV-1 plasmid DNA (pHxB-20) was used in the polymerase chain reaction (PCR). Amplification was performed using primers p1 and p2 to amplify the env region of chimeric A. Primers p3 and p4 were used to amplify the env region of chimeric B and primers p1 and p4 were used to amplify the env region of chimeric C as shown in FIG. 4. PCR was performed using the Perkin Elmer Cetus amplification kit and their cycler (Gene A mp PCR System 9600). The amplification reaction was denatured by heating to 95° C. for 20 seconds, then annealed at 68° C. for 15 seconds and extended at 72° for 45 seconds. A total of 30 cycles were performed.

b) Cloning and Bgl II Digestion

The PCR product of each of the env sequences was inserted into the TA cloning vector using the manufacturer's procedures (TA cloning kit, Invitrogen). Using the same kit, transformation of E. coli competent cells was performed and recombinant white colonies were picked up and grown in LB medium. DNA was extracted from the cells using published procedures and was used for digestion. This DNA was digested to completion with Bgl II (Gibco BRL), which incises twice in the plasmid at each of the two primers and hence releases the PCR product and introduces Bgl II sticky ends. This DNA was then ligated to the Bgl II cut pAcyM1 (at position 1310 nucleotides) vector, which contains the truncated HIV-1 gag DNA sequence. The ligated DNA was then introduced into E. coli competent cells and recombinant white colonies were grown in LB media. This DNA was extracted and used for Bam H1 digestion.

c) Barn H1 Digestion and Cloning Into pVL1393

The plasmid pAcYM 1, which contained the recombinant gag/env sequences, was digested with Bam H1 (Gibco BRL) in order to release the entire insert. This DNA was then ligated to Bam H1 cut pVL1393 (BaculoGold transfection vector). After ligation and transformation of E. coli competent cells, white colonies were grown in LB and DNA was extracted and purified.

d) Cotransfection

An equivalent of 5 μg of recombinant pVL1393 was used in the cotransfection procedure. This procedure was performed as recommended by the manufacturer (BaculoGold transfection kit, Pharminogen).

It will be understood by a person skilled in the art that while the present application only describes the preparation of three chimeric proteins, other chimeric proteins could be made and used as well in the immunofluorescence assay. Chimeric proteins containing conservative regions and having at least an antigenic or immunoreactive domain or epitope could also be used for the present invention.

EXAMPLE 2 Construction of Recombinant Baculovirus to Express HIV-1 gp160

A 5' end primer and 3' end primer having the following sequences:

    5'end primer           (SEQ ID NO: 17)                                         CGC TGA TCA ATG AGA GTG HAG GAG AAA TAT CAG C                                    3'end primer             (SEQ ID NO: 18)                                     CGC TGA TCA TTA TAG CAA AAT CCT TTC CAA GCC C                             

were designed to amplify the entire HIV-1 gp160 coding sequence (env open reading frame) (Ratner et al., Nature 313, 277-284) by polymerase chain reaction (PCR). In addition, a BcL1 enzyme recognition sequence was included in each of the primers to facilitate cloning of the coding sequence into a vector plasmid. After the gp160 gene was cloned and inserted into a baculovirus transfer vector pvl 1393, by techniques well known in the art, the co-transfection was performed using the procedure provided by the Baculo-Gold System (Pharmigen). The recombinant virus was isolated to express a fully glycosylated gp160 polyprotein, the precursor of HIV-1 env gene products.

EXAMPLE 3 Construction of Recombinant Baculovirus to Express HIV-1 pol 97

The recombinant virus expressing pol 97 was constructed as disclosed in Hu et al., 1991, Proc. Natl. Acad. Sci., 88, 4596-4600.

EXAMPLE 4 SF9 Cell Culture and HIV Recombinant Protein Production

Spodoptera frugiperda (Sf9) cells are grown in monolayer (175 cm² Falcon tissue culture flasks) or roller bottle (850 cm² cell culture bottles) cultures. The medium used for either culture condition is Gibco BRL Sf900 medium supplemented with 100 U/ml each of sodium penicillin G and streptomycin sulphate (Gibco BRL) or Sigma TNM-FH medium supplemented with 10% (v/v) fetal bovine serum (Gibco BRL) and 100 U/ml each of the above antibiotics.

The cells are infected at an moi of 5-10 with recombinant baculovirus (Autographa californica). Harvest of the intracellular protein (protein contained within the cells prior to cell lysis) was done using the same procedure for both the monolayer and roller bottle cultures after an optimum time of 72 hours post infection. The cells were released from the surface of the flask or bottle and the suspension was spun down for 10 minutes at 250×g at ambient temperature on a Beckman GP centrifuge. The cell pellet and the supernatant were then further processed. The supernatant (extracelluar protein) was transferred to Beckman Ultraclear tubes and spun down on a Beckman L8-80M ultracentrifuge at 26,000 rpm (SW28 rotor) at 20° C. for 1.5 hours. The pellet was resuspended in 1-2mL of phosphate buffered saline (PBS, 2.67 mM KCl, 1.15 mM KH₂ PO₄ 137.9 mM NaCl, 8.06 mM Na₂ HPO₄ pH 7.4) and then stored at -70° C. until use.

The cell pellet was washed in 30 mL of PBS and spun down again in the GP centrifuge. The pellet was resuspended in 10 mL of PBS then sonicated on ice for 45-50 seconds at 40% power (Cole-Parmer Ultrasonic Homogenizer 4710). The cell lysates were spun down on the GP centrifuge at 900×g for 10 minutes. The pellet fraction I, was resuspended in 1-2 mL of PBS and was held at 4° C. until use. The supernatant was spun down in a Sorvall RC-5 centrifuge with an SS-34 rotor at 10,000 rpm at 4° C. for 30 minutes. The pellet fraction II, was resuspended in 1-2 mL of PBS and held at 4° until use. The supernatant was spun down on the Beckmann ultracentrifuge under the same conditions as the extracelluar protein. The resulting pellet, fraction III, was resuspended in 1-2 mL of PBS and the supernatant was discarded. Fractions II and III were combined to form the intracellular protein stock. The resulting pellet was further purified by sucrose gradient (20%-60%) ultracentrifugation at 26000K rpm (SW28 rotor) for 3 hours at 20° C. The purified insoluble proteins were washed in PBS and then spun down on an IEC Micro-MB centrifuge for 5 minutes at room temperature. The pellet was washed twice more then stored at -70° C. until further use.

EXAMPLE 5 Flow Cytometry--r-FIFA Assay for the Detection of HIV-1 Antibodies

1. Flow Cytometry

Flow cytometric analysis was performed on a Becton Dickinson FACSort equipped with an argon ion laser tuned at 488 nm. Data acquisition was done with Lysus II 2.0 software, version 1.1 (Becton Dickinson). Forward light scattering, orthogonal light scattering and two fluorescent signals were determined on logarithmic settings for each of 20,000 events and stored in data files. Detector settings had been determined and stored in data files for recall by the operator. Data analysis was also performed with the Lysis 2.0 software. A two dimensional dot intensity plot of forward light scatter versus orthogonal light scatter was observed on ungated events. A region (R1) was set on the dot plot and single parameter histograms of FL1 (green emission for FITC is 530 nm) and FL2 (red emission for R-PE is 585 nm) were examined. The median fluorescence channel was used to determine positivity of the test samples. This analysis procedure has also been automated and stored as a command file.

2. r-FIFA Procedure

In 1.5 mL microcentrifuge tubes (Sarstedt) 4 μL of control or sample (plasma or serum) and a pre-determined amount of recombinant protein were combined along with PBS (containing NaN₃) to a final volume of 100 μL. Most of the tests were done with a mixture of gag-p45 and gag-gp41-B recombinant proteins. The rest were done with a single antigen as indicated. The tubes were gently vortexed then incubated at ambient temperature for 20 minutes on a rocker. The mixture was washed in 1 mL of PBS/tube and spun down for 5 minutes, ambient temperature at 12 700×g on an IEC Micro-MB centrifuge (fixed speed). The supernatant was aspirated and the pellet was gently resuspended in 1mL PBS and spun down as before. The supernatant was aspirated and 10 μL of FITC and/or R-PE labelled antibody is added. The mixture was incubated for 20 minutes at ambient temperature in the dark then washed two times with 1 ml/tube of PBS as before. After the second aspiration, 500 μL of PBS was added to each sample tube and the mixture was sonicated for 10 seconds at the 40% power setting with a 2 mm diameter probe attachment. The contents were then transferred to 12×75 mm polystyrene tubes (Becton-Dickinson, specific for the flow cytometer) and stored for 2 hours in the dark at ambient temperature then read on the flow cytometer.

To determine the cut-off values of fluorescence intensity for r-FIFA for each of the antigens (gag-p45, gag-gp41-C, pol97, and the mixture of gag-p45 and gag-gp41-B proteins) 100 normal donors were tested by using double staining with IgG FITC and IgM R-PE. Each sample was tested in duplicate and reported in relation to the mean value of a known seronegative control (S/N). The cut-off value was calculated by taking the mean S/N value of the population (x) and adding two standard deviations (2 SD) as described by Sligh (Sligh, 1989, Amer. J. Clin. Pathol. 91, 210-214). For example, the cut-off value of fluorescence intensity of gag-p45 was calculated as follows: ##EQU1##

Sample to cut-off (s/c) ratios of 1.0 or greater are considered positive.

EXAMPLE 6 Sensitivity and Reproducibility of r-FIFA

In order to determine the optimal serum or plasma dilution required for the sensitivity test of r-FIFA, an HIV-1 seropositive plasma and a control (negative plasma) were treated with gag-p45 as the antigen. FIG. 8 shows the fluorescence histograms of the samples at different dilutions. The fluorescence intensity of the positive sample sharply decreased as the dilution increased. It was positive at 1:6400 (s/c=1.25). The 1:25 dilution was shown to be the optimal sample dilution for r-FIFA and this dilution was used for further experiments.

Table 1 summarizes the results of r-FIFA for detection and analysis of eight BBI anti-HIV-1 seroconversion panels and compares the sensitivity of r-FIFA with currently licensed tests. Anti-HIV-1 antibodies were detected by r-FIFA in the first bleed of seven BBI panels. The average increase in sensitivity was greater than 20 days. FIG. 9 illustrates the fluorescence histograms of samples in Panel D. The HIV-1 antibody (IgM) had become positive three months before antibodies were detected by EIA. The antibody titer dropped in sample D3 possibly because of HIV antigen-antibody complex formation.

To evaluate the reproducibility of r-FIFA, two antigens gag-p45 and gag-gp41-C were used for the analysis of panel D. The results of the two assays were almost identical. The duplicates of each assay were highly reproducible as shown by the overlapping of two line peaks which represent the fluorescent intensity of each sample. In addition to the BBI panels, three HIV-1 seroconversion panels from PHL were evaluated in a blind test to confirm the sensitivity of r-FIFA (FIG. 10). The first bleed of all three patients was seronegative in EIA and WB tests. However, IgG and IgM HIV-1 antibodies were detected by r-FIFA. The antibody response pattern of the three panels suggests that the patients were infected recently since IgM was the dominant antibody. The first bleed from the patient PHL-A (who donated blood for a transfusion) was negative by EIA in 1988. The recipient was infected by the seronegative but HIV-1 infected blood. The donor was identified as HIV-1 positive by testing in 1993 with a recently licensed test which used conjugated second antibody to both human IgG and IgM. The 1988 sample was still negative by this test but the 1993 sample was strongly positive. In r-FIFA, both the 1988 and the 1993 samples were positive for IgG and IgM. Furthermore, to compare the sensitivity of r-FIFA with that of FDA licensed confirmatory tests including WB, and radioimmunoprecipitation (RIPA), the BBI anti-HIV-1 1 ow titer panel was tested with r-FIFA using each of the antigens gag-p45, gag-gp41 chimeric proteins and pol97. The results are summarized in Table 2 and show that r-FIFA is more sensitive than any of the FDA licensed confirmatory tests. The antibodies to gag and env or to all three of these antigens were positive by r-FIFA in 12 of the 14 samples. Only 8 to 10 were positive in the four confirmatory tests. The results show that the pol97 is an excellent antigen for HIV-1 antibody detection. Antibodies to pol97 were detectable in 8 out of the 14 samples in r-FIFA. However, the antibodies to pol gene products (p68, p51 and p31) were poorly detected in the FDA licensed confirmatory tests. Only 1 to 4 of the 14 samples were found to have antibodies to pol proteins on WB and RIPA. It has been reported that antibodies to gag-encoded proteins appear first, followed closely by those antibodies to env glycoproteins, then pol reactivity to p66 appear on WB. Our studies show that the antibodies to pol97 were detected as early as those to gag-p45 and gag-gp41 chimeric proteins as shown in FIG. 15. This provides evidence to the effect that antibodies to pol gene products are one of the important serological markers for early diagnosis of HIV-1 infection and monitoring of HIV-1 infection disease progression.

EXAMPLE 7 Specificity of r-FIFA

295 random donor samples, 105 EIA/WB positive samples and 128 EIA repeat reactive or positive/WB indeterminate samples were tested by r-FIFA. Only 1 of the 295 random donor samples was positive. One of the positive samples from the random donor was negative in EIA but was positive by radioimmunoprecipitation (r-RIPA). All 105 positive samples were positive by r-FIFA. Only 30 of 128 (23%) EIA repeat reactive WB indeterminate samples were still positive. These results indicate that r-FIFA's specificity is higher than that of EIA and WB.

EXAMPLE 8 Antibody Response During the Window Period

FIG. 11 demonstrates the patterns of HIV-1 antibody production in eight BBI panels. A typical primary response was found in panels J and K. Panels D and R show a similar pattern of antibody production. However, in panels E, H, P and Q, the HIV-1 IgG antibody remained at a certain level for a long period (over two or three months) prior to seroconversion as detected by licensed tests. The IgM antibody became positive later at a low level or at the same time (panel Q) as did IgG antibodies. The pattern of E, H, P and Q is apparently different from the pattern of D, J, K and R. Presumably these individuals were not recently infected by HIV-1. For some reason, virus-antigen concentration rose, stimulating the antibody response. The anti-HIV-1 IgG antibodies jumped up to a high level in a shorter time (less than a week as seen in Q and R) indicating a possible secondary immune response. FIG. 12 shows the fluorescence histograms of the samples in panel K, indicating the kinetics of the specific IgG, IgM and IgA production during the window period. The IgM antibodies were detected first before the antigen was detected, and then IgA and IgG antibodies appeared about two weeks after the antigen level peaked. The IgM antibody response to HIV-1 proteins overlapped with the HIV-1 antigen peak and started before the antigen was detected.

EXAMPLE 9 Differences in Antibody Response to Different Antigens gag-p45, gag-gp41-C and pol97 in r-FIFA

Chimeric gag-gp41-C binds more IgG antibodies than gag-p45 and detects them earlier. Little difference was found in detection of HIV-1 IgM antibodies (FIGS. 13 and 14). HIV-1 IgG antibodies to pol97 were detected as early as gag-gp41-C (FIG. 15). IgM antibody to pol97 was very low during this "window" period.

EXAMPLE 10 Comparison of r-FIFA Assay with gag-p45, gag-gp 41-C, pol97, gp 160 and Mixture of gag-45, pol97 and gp 160

In a preferred embodiment, a mixture of equal amounts of gag-p45, pol97 and gp 160 is used in the r-FIFA. The proteins were prepared as described in the previous examples and the r-FIFA was conducted as previously described. An anti-HIV-1 low titer performance panel (PRB 104) was utilized. The results are reported in Table 3. The testing with a mixture of all three proteins was carried out with 5 samples. The results with the mixture were positive in all instances. This shows the sensitivity of the procedure with a mixture of the proteins. In instances where the results were negative for each of the four proteins individually, the results with the mixture were negative as well (sample 10) and where the results were positive with each of the proteins individually, the results of the mixture were positive as well (sample 7). The use of a mixture of the proteins is advantageous in a situation where the results with each of the proteins all not all positive or negative (samples 3, 11 and 14). In all instances where some of the individual results were negative, the use of a mixture of proteins allowed a final determination and gave positive results. The gag, gp and pol polyproteins cover over 90% of the viral structural proteins and allow r-FIFA to be used as a confirmatory test because of its high sensitivity, specificity and its ability to identify antibodies directed to individual HIV-1 polyproteins.

EXAMPLE 11 Flow Cytometry--r-FIFA Assay for the Detection of Hepatitis B Antibodies

The Hepatitis B core antigen was prepared as is known in the art and as is described for example in Takehara et al., 1988, J. Gen. Virology, 69:2763-2777. Recombinant baculoviruses were constructed to express the hepatitis B core antigen in the same manner as described in Example 1 in relation to HIV-1 gag p45 and chimeric gag-gp 41 proteins. The r-FIFA assay for the detection of antibodies to Hepatitis B core antigens was conducted as set out in Example 5 in relation to the detection of HIV-1 antibodies. The results of a comparison of sensitivity between licensed EIA and RIA tests for Hepatitis B and r-FIFA using standard BBI panels are set out in Table 4.

The above examples demonstrate that r-FIFA is more sensitive than licensed screening and confirmatory tests for detection of early antibodies to HIV-1. At least one class of anti-HIV-1 specific IgG, IgM or IgA was detected during the window period of HIV-1 infected individuals. We have created a unique way to detect early antibodies using insoluble forms of recombinant proteins as autologous carriers through a flow cytometer. Two patterns of antibody response were observed, which may represent two types of immune response: primary and secondary.

On average for the tests which were in use in 1990 the window period was 45 days. Since then the tests have increased sensitivity for HIV antibody detection resulting in earlier detection of seroconversion and a significant decrease of approximately 12-13 days in the length of the infectious window period (Dodd, 1990, Arch. Pathol. Lab. Med. 114, 240-245). An analysis of the records made in 19 American National Red Cross regions in 1992 and 1993 showed that the window period estimated using third generation tests was 25 days on average Petersen et al., 1994, Transfusion 34,283-289). As shown in Table 1, the average increase in sensitivity using the method of the present invention was greater than 20 days. The r-FIFA of the present invention is a novel serological test, which uses insoluble polyproteins. The insoluble antigens are easily processed and purified without denaturation, keeping intact their natural molecular folding which may optimize the presentation of antigen epitopes. This may be one of the explanations to account for r-FIFA's higher sensitivity in detection of HIV-1 early antibodies. Furthermore, an agglutination effect involving the reaction between IgM antibodies and the antigens in r-FIFA may enhance the sensitivity for detection of specific antibodies because all the insoluble polyproteins used are particulate antigens. This is demonstrated in FIG. 16. In general, IgM antibodies are more efficient in agglutination than IgG antibodies because of their size as well as their additional binding sites.

The assay of the present invention (r-FIFA) is much more sensitive than any of the currently licensed tests used for analysis of BBI seroconversion panels to detect very early HIV-1 antibodies during the "window" period. Both anti-HIV-1 specific IgG and IgM have been found prior to the seroconversion of seroconversion panels. Some of them contain primarily anti-HIV-1 IgG or IgM. Some individuals have both anti-HIV-1 IgG and IgM. This appears to depend on the time of primary infection, appearance of antigenemia and the situation of the immune system of the HIV-1 infected individuals. Detection, quantification and differentiation of anti-HIV-1 antibodies in the "window" period have permitted a further understanding of the immune response and HIV-1 immunopathogenesis in this "immunological silent" period. The development of r-FIFA has allowed the use of insoluble proteins as antigens to detect antibodies. These insoluble proteins can be easily produced on a large scale using a baculovirus expression system.

While the r-FIFA procedure for use in the detection of HIV-1 infection is described in relation to gag p45, gag-gp 41, gp 160 and pol97 recombinant proteins, it will be understood that a mixture of these proteins as exemplified in Example 10 can be used as well as any number of other proteins and need not be recombinant proteins prepared in the baculovirus expression system. The proteins are not limited to those specifically exemplified. While the examples and the results set out above pertain to the use of the recombinant proteins in the detection and treatment of HIV-1, it is understood that the examples are not meant to be limiting. The invention would have applicability to the detection and treatment of HIV-2 using an insoluble form of a protein equivalent to gag p45 in HIV-1 as well as have applicability in the detection and treatment of other viral infections. This is illustrated in Example 11 where r-FIFA is used in the detection of hepatitis B. The invention also has applicability in the detection of other viral infections such as hepatitis C, HTLV-1/2 (human T-cell leukemia) or HTLV-II and has applicability for any virus-mediated condition where the virus proteins exist in insoluble form. Indeed, it is not limited to the detection of viral infections but has application for the detection of any disease state where an insoluble form of an antigen can be used in the assay of the present invention for the detection of antibodies. It is also contemplated that chimeric proteins can be constructed comprising several antigenic domains so that one test could be used for the detection of several disease states, for example, HIV-1/2, HTLV-1/2, hepatitis B and hepatitis C.

Furthermore, it is also understood that where recombinant proteins are used in the assay of the present invention, any expression system sharing the advantages of the baculovirus expression system could also be used.

All publications referred to in the disclosure are hereby incorporated by reference.

While the present invention has been described in connection with a specific embodiment thereof and in a specific use, various modifications will occur to those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims. I therefore wish to embody within the scope of the patent which may be granted hereon all such embodiments as reasonably and properly come within the scope of my contribution to the art.

                                      TABLE 1                                      __________________________________________________________________________     Comparison of the Sensitivity Between r-FIFA and Licensed Tests for             HIV-1 Antibodies in Anti-HIV-1 Seroconversion Panels (BBI)                              Time                                                                                                                     # of Span Members                                                             Antibody Reactivity of                                                         Each Panel Member           Code                                                                               Members                                                                              (Days)                                                                              Antigen +                                                                            1  2  3  4  5  6  7  8  9  10 Tests                       __________________________________________________________________________     D   5     101  0     -  -  -  +  +                 EIA                               + + (+) + +      r-FIFA                                                    E 10 126 2 - - - - - - - - - + EIA                                                 + + + (+) - + (+) + + + r-FIFA                                             H 6 28 0 - - - - - +     EIA                                                       + + + + (+) +     r-FIFA                                                   J 7 40 0 - - + + + + +    EIA                                                      + + + + + + +    r-FIFA                                                    K 10 36 0 - - - (+) (+) (+) (+) + + + EIA                                          + + + + + + + + + + r-FIFA                                                 P 6 35 1 - - - - + +     EIA                                                       + + (+) + + +     r-FIFA                                                   Q 7 72 5 - - - - (+) (+) +    EIA                                                  + + - (+) + + +    r-FIFA                                                  R 6 21 2 - (+) (+) + + +     EIA                                                   - (+) + + + +     r-FIFA                                                 __________________________________________________________________________      EIA data shown in this table is a summary of 13 licensed test results fro      BBI. Both antiHIV-specific IgG and IgM were detected by rFIFA using            fluorescence conjugated second antibodies to human IgG and IgM. The            antiHIV-1 antibodies IgG and IgM were detected separately by double            staining with IgG FITC and IgM RPE. If the s/c value ≧ 0.9 but <        1.0 it is considered to be weak reactive (+); the s/c value of 1.0 or          greater is considered positive +. The weak reactivity  # (+) by EIA means      that the sample is positive in some tests and negative in others.        

                                      TABLE 2                                      __________________________________________________________________________     Comparison between r-FIFA and FDA licensed confirmatory tests based on          sensitivity for detection of antibodies to HIV-1 proteins encoded in the       three open reading frames of HIV-1 genome in the anti-HIV-1 low titer         panel PRB104                                                                           FDA Licensed Tests                                                     PRB104 I.D.                                                                            BioRad WB* Ortho/Cambridge WB                                                                        Organon Teknika WB                                                                        HIV-1 RIPA RL15                                                                           HIV-1 r-FIFA               Number  gag                                                                               pol                                                                              env                                                                               Res.                                                                              gag                                                                               pol                                                                              env                                                                               Res.                                                                              gag                                                                               pol                                                                              env                                                                               Res.                                                                              gag                                                                               pol                                                                              env                                                                               Res.                                                                              gag                                                                               pol                                                                              env.sup.†                                                                  Res.               __________________________________________________________________________     01      +  - +  +  +  + +  +  +  - +  +  +  - +  +  +  + +  +                    02 + - + + + - + + + - + + + - + + + - + +                                     03 + - + + + - + + + + + + + + + + + - + +                                     04 + - + + + - + + + - + + + - + + + + + +                                     05 + - + + + + + + + + + + + + + + + + + +                                     06 + + + + + - + + + + + + + + + + + + + +                                     07 + - - IND + - - IND + - - IND - - + IND + + + +                             08 - - - - + - - IND + - - IND - - + IND + + + +                               09 + - + + + - + + + - + + - - + IND + + + +                                   10.sup.‡ - - - - - - - - - - - - - - - - - - - -                    11 + - + + + - + + + - + + + - + + + - + +                                     12 + - + + + - + + + - + + + + + + + - + +                                     13 + - + + + - - IND + - f160 + - - + IND + + + +                              14 f24 - - IND - - - - f24 - - IND - - + IND + - - IND                         15 -  - - - - - - - - - - - - - - - - - - -                                    TOTAL 12 1 10 10 12 2 9 9 13 3 10 10 8 4 13 8 13 8 12 12                       POSITIVES                                                                    gag + env + =                                                                          71%        64%        71%        57%        86%                          gag + pol +  7% 14% 21% 29% 57%                                                env + =                                                                      __________________________________________________________________________      *Western Blots were interpreted using CDC/ASTPHLD criteria. All Western        Blots were performed at Boston Biomedica.                                      .sup.† The chimeric gaggp41(C, B) was used for detection of             antibodies to env. Later, the results were confirmed using insoluble gp16      polyprotein as antigen in rFIFA.                                               .sup.‡ PRB104 10 is the negative control.                           f = faint, + = positive, - = negative, IND = indeterminate, RES = result 

                  TABLE 3                                                          ______________________________________                                         Detection of Antibodies to HIV-1 in Samples of Anti-HIV-1 Low Titer             Performance Pabels (PRB104) using Different Antigens                                  ANTIGENS                                                                                                      mixture of                                     gag-p45,                                                                  PRB104 I.D. gag-p45 gag-gp41-C pol97 gp160 pol97 and                           NUMBER s/c s/c s/c s/c gp160 s/c                                             ______________________________________                                         01      1.64     1.18      1.10  1.17  ND                                        02 1.35 1.20 0.80 1.24 ND                                                      03 1.11 1.29 0.87 1.00 2.30                                                    04 1.31 1.31 1.10 1.37 ND                                                      05 1.49 1.08 1.47 1.03 ND                                                      06 2.20 1.22 1.70 1.23 ND                                                      07 1.27 1.00 1.80 1.00 1.36                                                    08 1.36 1.06 1.24 1.22 ND                                                      09 1.34 1.00 1.32 1.00 ND                                                      10 0.89 0.63 0.61 0.72 0.71                                                    11 1.45 1.04 0.80 1.00 1.46                                                    12 1.38 1.06 0.79 1.16 ND                                                      13 1.59 0.93 1.47 1.22 ND                                                      14 1.09 0.78 0.58 0.78 1.16                                                    15 0.81 0.77 0.86 0.54 ND                                                    ______________________________________                                    

                                      TABLE 4                                      __________________________________________________________________________     Comparison of Sensitivity Between Licensed Tests and r-FIFA in                   Detection of Antibodies to HBc                                                                                             HBsAg                                                                               ANTI-HBs                        ANTI-HBc ANTI-HBc ANTI-HBc ANTI-HBc  ABBOTT ABBOTT                             IgM ABBOTT IgM ABBOTT IgM ABBOTT IgM ABBOTT ANTI-HBc RIA EIA ANTI-HBc        MEMBER  EIA PROC A EIA PROC B RIA PROC A RIA PROC B IgM SORIN PROC A                                                                  PROC B r-FIFA         I.D.  MA- (S/CO) (S/CO)  (S/CO) (S/CO)  EIA   (S/CO)                                                                              (S/CO)                                                                               IgG                                                                               IgM                NUMBER                                                                               TRIX                                                                               BBI    BBI RL1 BBI    BBI RL1 BBI   BBI  BBI   (s/c)                                                                             (s/c)              __________________________________________________________________________     PHE201-01                                                                            P   4.5    4.8 4.7 5.8    5.3 9.2 8.2   114  0.2   5.6                                                                               2.7                  PHE201-02 P 4.0 3.9 4.6 4.8 5.1 6.0 9.9 99 0.2 8.7 2.71                        PHE201-03 P 13.0 5.5 4.6 11.5 12.7 13.1 12.0 100 0.2 7.33 6.09                 PHE201-04 P 0.4 0.5 0.6 0.5 0.5 0.6 2.2 131 0.4 0.58 0.52                      PHE201-05 P 6.5 5.1 4.6 5.0 6.0 8.2 10.1 5 0.2 6.93 4.66                       PHE201-06 P 3.0 3.0 4.1 3.3 2.7 4.2 7.9 106 0.2 5.55 2.11                      PHE201-07 P 2.7 2.4 3.7 3.7 4.0 4.3 8.6 26 0.1 6.83 2.46                       PHE201-08 P 3.7 3.3 4.6 3.5 4.3 5.9 10.5 117 0.2 7.60 4.19                     PHE201-09 S 3.7 3.5 4.3 3.7 3.5 5.0 9.6 129 0.1 7.08 2.84                      PHE201-10 P 1.5 1.8 3.5 1.6 1.9 4.5 5.3 98 0.2 3.87 2.72                       PHE201-11 P 0.4 0.5 0.8 0.4 0.4 0.5 1.8 94 0.6 3.72 0.81                       PHE201-12 P 7.3 5.5 4.7 6.7 7.8 9.1 10.1 15 0.2 3.62 4.71                      PHE201-13 P 5.5 4.4 4.7 6.8 5.2 7.3 10.4 88 0.2 8.60 4.71                      PHE201-14 P 5.8 5.1 4.7 5.6 6.3 8.0 10.6 96 0.2 4.44 3.42                      PHE201-15 S 8.5 8.1 4.7 9.0 10.0 10.8 11.2 113 0.1 9.25 5.94                   PHE201-16 P 9.1 5.5 4.7 8.3 8.4 10.8 11.0 103 0.2 9.77 5.16                    PHE201-17 P 5.1 5.0 4.7 7.0 7.1 8.9 10.9 103 0.2 8.55 3.64                     PHE201-18 S 1.8 1.9 2.6 1.7 2.0 2.6 6.8 80 0.1 6.65 2.6                        PHE201-19 S 3.9 3.0 4.1 3.0 3.0 4.8 8.5 108 0.2 5.04 3.54                      PHE201-20 S 2.2 2.4 2.6 2.2 2.7 2.1 6.3 117 0.2 7.88 2.59                      PHE201-21 P 3.1 2.8 3.3 2.7 2.5 3.7 8.2 128 0.1 5.41 2.11                      PHE201-22 P 2.5 3.1 3.1 2.6 2.4 3.7 8.9 101 0.2 1.54 1.17                      PHE201-23 P 2.1 2.3 2.8 2.8 2.7 2.6 6.1 152 0.2 6.55 1.89                      PHE201-24 P 3.8 2.8 3.8 2.5 3.4 4.0 8.9 113 0.3 2.69 1.87                      PHE201-25 P 2.7 3.1 4.2 2.9 3.3 4.3 10.3 114 0.2 9.13 4.89                   __________________________________________________________________________      All panel members have been found positive by a test for HBsAg and             negative by a test for antiHIV-1.                                              EIA and RIA results were generated using commercially available FDA            approved antiHBc IgM screening tests, performed at BBI and at a nationall      recognized noncommercial referee laboratory (RL1) by individuals who           routinely use these procedures. All numeric results are means of               duplicates, expressed as specimen absorbance to cutoff ratios (s/co).          Ratios ≧ 1.0 are considered reactive.                                   Specimens are undiluted aliquots form serum (S) or plasma (P) units            collected from asymptomatic blood donors in 1989 and 1990.               

    __________________________________________________________________________     #             SEQUENCE LISTING                                                    - -  - - (1) GENERAL INFORMATION:                                              - -    (iii) NUMBER OF SEQUENCES: 21                                           - -  - - (2) INFORMATION FOR SEQ ID NO:1:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 1314 base - #pairs                                                 (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:                                - - ATGGGTGCGA GAGCGTCAGT ATTAAGCGGG GGAGAATTAG ATCGATGGGA AA -             #AAATTCGG     60                                                                  - - TTAAGGCCAG GGGGAAAGAA AAAATATAAA TTAAAACATA TAGTATGGGC AA -             #GCAGGGAG    120                                                                  - - CTAGAACGAT TCGCAGTTAA TCCTGGCCTG TTAGAAACAT CAGAAGGCTG TA -             #GACAAATA    180                                                                  - - CTGGGACAGC TACAACCATC CCTTCAGACA GGATCAGAAG AACTTAGATC AT -             #TATATAAT    240                                                                  - - ACAGTAGCAA CCCTCTATTG TGTGCATCAA AGGATAGAGA TAAAAGACAC CA -             #AGGAAGCT    300                                                                  - - TTAGACAAGA TAGAGGAAGA GCAAAACAAA AGTAAGAAAA AAGCACAGCA AG -             #CAGCAGCT    360                                                                  - - GACACAGGAC ACAGCAGTCA GGTCAGCCAA AATTACCCTA TAGTGCAGAA CA -             #TCCAGGGG    420                                                                  - - CAAATGGTAC ATCAGGCCAT ATCACCTAGA ACTTTAAATG CATGGGTAAA AG -             #TAGTAGAA    480                                                                  - - GAGAAGGCTT TCAGCCCAGA AGTAATACCC ATGTTTTCAG CATTATCAGA AG -             #GAGCCACC    540                                                                  - - CCACAAGATT TAAACACCAT GCTAAACACA GTGGGGGGAC ATCAAGCAGC CA -             #TGCAAATG    600                                                                  - - TTAAAAGAGA CCATCAATGA GGAAGCTGCA GAATGGGATA GAGTACATCC AG -             #TGCATGCA    660                                                                  - - GGGCCTATTG CACCAGGCCA GATGAGAGAA CCAAGGGGAA GTGACATAGC AG -             #GAACTACT    720                                                                  - - AGTACCCTTC AGGAACAAAT AGGATGGATG ACAAATAATC CACCTATCCC AG -             #TAGGAGAA    780                                                                  - - ATTTATAAAA GATGGATAAT CCTGGGATTA AATAAAATAG TAAGAATGTA TA -             #GCCCTACC    840                                                                  - - AGCATTCTGG ACATAAGACA AGGACCAAAA GAACCTTTTA GAGACTATGT AG -             #ACCGGTTC    900                                                                  - - TATAAAACTC TAAGAGCCGA GCAAGCTTCA CAGGAGGTAA AAAATTGGAT GA -             #CAGAAACC    960                                                                  - - TTGTTGGTCC AAAATGCGAA CCCAGATTGT AAGACTATTT TAAAAGCATT GG -             #GACCAGCG   1020                                                                  - - GCTACACTAG AAGAAATGAT GACAGCATGT CAGGGAGTAG GAGGACCCGG CC -             #ATAAGGCA   1080                                                                  - - AGAGTTTTGG CTGAAGCAAT GAGCCAAGTA ACAAATACAG CTACCATAAT GA -             #TGCAGAGA   1140                                                                  - - GGCAATTTTA GGAACCAAAG AAAGATGGTT AAGTGTTTCA ATTGTGGCAA AG -             #AAGGGCAC   1200                                                                  - - ACAGCCAGAA ATTGCAGGGC CCCTAGGAAA AAGGGCTGTT GGAAATGTGG AA -             #AGGAAGGA   1260                                                                  - - CACCAAATGA AAGATTGTAC TGAGAGACAG GCTAATTTTT TAGGGAAGAT CT - #AA              1314                                                                        - -  - - (2) INFORMATION FOR SEQ ID NO:2:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 437 amino - #acids                                                 (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:                                - - Met Gly Ala Arg Ala Ser Val Leu Ser Gly Gl - #y Glu Leu Asp Arg Trp       1               5   - #                10  - #                15                - - Glu Lys Ile Arg Leu Arg Pro Gly Gly Lys Ly - #s Lys Tyr Lys Leu Lys                   20      - #            25      - #            30                    - - His Ile Val Trp Ala Ser Arg Glu Leu Glu Ar - #g Phe Ala Val Asn Pro               35          - #        40          - #        45                        - - Gly Leu Leu Glu Thr Ser Glu Gly Cys Arg Gl - #n Ile Leu Gly Gln Leu           50              - #    55              - #    60                            - - Gln Pro Ser Leu Gln Thr Gly Ser Glu Glu Le - #u Arg Ser Leu Tyr Asn       65                  - #70                  - #75                  - #80         - - Thr Val Ala Thr Leu Tyr Cys Val His Gln Ar - #g Ile Glu Ile Lys Asp                       85  - #                90  - #                95                - - Thr Lys Glu Ala Leu Asp Lys Ile Glu Glu Gl - #u Gln Asn Lys Ser Lys                   100      - #           105      - #           110                   - - Lys Lys Ala Gln Gln Ala Ala Ala Asp Thr Gl - #y His Ser Asn Gln Val               115          - #       120          - #       125                       - - Ser Gln Asn Tyr Pro Ile Val Gln Asn Ile Gl - #n Gly Gln Met Val His           130              - #   135              - #   140                           - - Gln Ala Ile Ser Pro Arg Thr Leu Asn Ala Tr - #p Val Lys Val Val Glu       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Glu Lys Ala Phe Ser Pro Glu Val Ile Pro Me - #t Phe Ser Ala Leu         Ser                                                                                              165  - #               170  - #               175              - - Glu Gly Ala Thr Pro Gln Asp Leu Asn Thr Me - #t Leu Asn Thr Val Gly                   180      - #           185      - #           190                   - - Gly His Gln Ala Ala Met Gln Met Leu Lys Gl - #u Thr Ile Asn Glu Glu               195          - #       200          - #       205                       - - Ala Ala Glu Trp Asp Arg Val His Pro Val Hi - #s Ala Gly Pro Ile Ala           210              - #   215              - #   220                           - - Pro Gly Gln Met Arg Glu Pro Arg Gly Ser As - #p Ile Ala Gly Thr Thr       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Ser Thr Leu Gln Glu Gln Ile Gly Trp Met Th - #r Asn Asn Pro Pro         Ile                                                                                              245  - #               250  - #               255              - - Pro Val Gly Glu Ile Tyr Lys Arg Trp Ile Il - #e Leu Gly Leu Asn Lys                   260      - #           265      - #           270                   - - Ile Val Arg Met Tyr Ser Pro Thr Ser Ile Le - #u Asp Ile Arg Gln Gly               275          - #       280          - #       285                       - - Pro Lys Glu Pro Phe Arg Asp Tyr Val Asp Ar - #g Phe Tyr Lys Thr Leu           290              - #   295              - #   300                           - - Arg Ala Glu Gln Ala Ser Gln Glu Val Lys As - #n Trp Met Thr Glu Thr       305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - Leu Leu Val Gln Asn Ala Asn Pro Asp Cys Ly - #s Thr Ile Leu Lys         Ala                                                                                              325  - #               330  - #               335              - - Leu Gly Pro Ala Ala Thr Leu Glu Glu Met Me - #t Thr Ala Cys Gln Gly                   340      - #           345      - #           350                   - - Val Gly Gly Pro Gly His Lys Ala Arg Val Le - #u Ala Glu Ala Met Ser               355          - #       360          - #       365                       - - Gln Val Thr Asn Ser Ala Thr Ile Met Met Gl - #n Arg Gly Asn Phe Arg           370              - #   375              - #   380                           - - Asn Gln Arg Lys Ile Val Lys Cys Phe Asn Cy - #s Gly Lys Glu Gly His       385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - Thr Ala Arg Asn Cys Arg Ala Pro Arg Lys Ly - #s Gly Cys Trp Lys         Cys                                                                                              405  - #               410  - #               415              - - Gly Lys Glu Gly His Gln Met Lys Asp Cys Th - #r Glu Arg Gln Ala Asn                   420      - #           425      - #           430                   - - Phe Leu Gly Lys Ile                                                               435                                                                     - -  - - (2) INFORMATION FOR SEQ ID NO:3:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 354 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: CDS                                                              (B) LOCATION: 1..354                                                  - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:                                - - GGA GTA GCA CCC ACC AAG GCA AAG AGA AGA GT - #G GTG CAG AGA GAA AAA            48                                                                        Gly Val Ala Pro Thr Lys Ala Lys Arg Arg Va - #l Val Gln Arg Glu Lys              1               5 - #                 10 - #                 15               - - AGA GCA GTG GGA ATA GGA GCT TTG TTC CTT GG - #G TTC TTG GGA GCA GCA            96                                                                        Arg Ala Val Gly Ile Gly Ala Leu Phe Leu Gl - #y Phe Leu Gly Ala Ala                         20     - #             25     - #             30                   - - GGA AGC ACT ATG GGC GCA GCG TCA ATG ACG CT - #G ACG GTA CAG GCC AGA           144                                                                        Gly Ser Thr Met Gly Ala Ala Ser Met Thr Le - #u Thr Val Gln Ala Arg                     35         - #         40         - #         45                       - - CAA TTA TTG TCT GGT ATA GTG CAG CAG CAG AA - #C AAT TTG CTG AGG GCT           192                                                                        Gln Leu Leu Ser Gly Ile Val Gln Gln Gln As - #n Asn Leu Leu Arg Ala                 50             - #     55             - #     60                           - - ATT GAG GCG CAA CAG CAT CTG TTG CAA CTC AC - #A GTC TGG GGC ATC AAG           240                                                                        Ile Glu Ala Gln Gln His Leu Leu Gln Leu Th - #r Val Trp Gly Ile Lys             65                 - # 70                 - # 75                 - # 80        - - CAG CTC CAG GCA AGA ATC CTG GCT GTG GAA AG - #A TAC CTA AAG GAT CAA           288                                                                        Gln Leu Gln Ala Arg Ile Leu Ala Val Glu Ar - #g Tyr Leu Lys Asp Gln                             85 - #                 90 - #                 95               - - CAG CTC CTG GGG ATT TGG GGT TGC TCT GGA AA - #A CTC ATT TGC ACC ACT           336                                                                        Gln Leu Leu Gly Ile Trp Gly Cys Ser Gly Ly - #s Leu Ile Cys Thr Thr                        100      - #           105      - #           110                   - - GCT GTG CCT TGG AAT GCT         - #                  - #                       - # 354                                                                   Ala Val Pro Trp Asn Ala                                                                115                                                                     - -  - - (2) INFORMATION FOR SEQ ID NO:4:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 118 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:                                - - Gly Val Ala Pro Thr Lys Ala Lys Arg Arg Va - #l Val Gln Arg Glu Lys         1               5 - #                 10 - #                 15               - - Arg Ala Val Gly Ile Gly Ala Leu Phe Leu Gl - #y Phe Leu Gly Ala Ala                    20     - #             25     - #             30                   - - Gly Ser Thr Met Gly Ala Ala Ser Met Thr Le - #u Thr Val Gln Ala Arg                35         - #         40         - #         45                       - - Gln Leu Leu Ser Gly Ile Val Gln Gln Gln As - #n Asn Leu Leu Arg Ala            50             - #     55             - #     60                           - - Ile Glu Ala Gln Gln His Leu Leu Gln Leu Th - #r Val Trp Gly Ile Lys        65                 - # 70                 - # 75                 - # 80        - - Gln Leu Gln Ala Arg Ile Leu Ala Val Glu Ar - #g Tyr Leu Lys Asp Gln                        85 - #                 90 - #                 95               - - Gln Leu Leu Gly Ile Trp Gly Cys Ser Gly Ly - #s Leu Ile Cys Thr Thr                   100      - #           105      - #           110                   - - Ala Val Pro Trp Asn Ala                                                           115                                                                     - -  - - (2) INFORMATION FOR SEQ ID NO:5:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 342 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: CDS                                                              (B) LOCATION: 1..342                                                  - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:                                - - AGG GCT ATT GAG GCG CAA CAG CAT CTG TTG CA - #A CTC ACA GTC TGG GGC            48                                                                        Arg Ala Ile Glu Ala Gln Gln His Leu Leu Gl - #n Leu Thr Val Trp Gly              1               5 - #                 10 - #                 15               - - ATC AAG CAG CTC CAG GCA AGA ATC CTG GCT GT - #G GAA AGA TAC CTA AAG            96                                                                        Ile Lys Gln Leu Gln Ala Arg Ile Leu Ala Va - #l Glu Arg Tyr Leu Lys                         20     - #             25     - #             30                   - - GAT CAA CAG CTC CTG GGG ATT TGG GGT TGC TC - #T GGA AAA CTC ATT TGC           144                                                                        Asp Gln Gln Leu Leu Gly Ile Trp Gly Cys Se - #r Gly Lys Leu Ile Cys                     35         - #         40         - #         45                       - - ACC ACT GCT GTG CCT TGG AAT GCT AGT TGG AG - #T AAT AAA TCT CTG GAA           192                                                                        Thr Thr Ala Val Pro Trp Asn Ala Ser Trp Se - #r Asn Lys Ser Leu Glu                 50             - #     55             - #     60                           - - CAG ATT TGG AAT AAC ATG ACC TGG ATG GAG TG - #G GAC AGA GAA ATT AAC           240                                                                        Gln Ile Trp Asn Asn Met Thr Trp Met Glu Tr - #p Asp Arg Glu Ile Asn             65                 - # 70                 - # 75                 - # 80        - - AAT TAC ACA AGC TTA ATA CAC TCC TTA ATT GA - #A GAA TCG CAA AAC CAG           288                                                                        Asn Tyr Thr Ser Leu Ile His Ser Leu Ile Gl - #u Glu Ser Gln Asn Gln                             85 - #                 90 - #                 95               - - CAA GAA AAG AAT GAA CAA GAA TTA TTG GAA TT - #A GAT AAA TGG GCA AGT           336                                                                        Gln Glu Lys Asn Glu Gln Glu Leu Leu Glu Le - #u Asp Lys Trp Ala Ser                        100      - #           105      - #           110                   - - TTG TGG                - #                  - #                  -       #          342                                                                   Leu Trp                                                                         - -  - - (2) INFORMATION FOR SEQ ID NO:6:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 114 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:                                - - Arg Ala Ile Glu Ala Gln Gln His Leu Leu Gl - #n Leu Thr Val Trp         Gly                                                                                1               5 - #                 10 - #                 15              - - Ile Lys Gln Leu Gln Ala Arg Ile Leu Ala Va - #l Glu Arg Tyr Leu Lys                    20     - #             25     - #             30                   - - Asp Gln Gln Leu Leu Gly Ile Trp Gly Cys Se - #r Gly Lys Leu Ile Cys                35         - #         40         - #         45                       - - Thr Thr Ala Val Pro Trp Asn Ala Ser Trp Se - #r Asn Lys Ser Leu Glu            50             - #     55             - #     60                           - - Gln Ile Trp Asn Asn Met Thr Trp Met Glu Tr - #p Asp Arg Glu Ile Asn        65                 - # 70                 - # 75                 - # 80        - - Asn Tyr Thr Ser Leu Ile His Ser Leu Ile Gl - #u Glu Ser Gln Asn Gln                        85 - #                 90 - #                 95               - - Gln Glu Lys Asn Glu Gln Glu Leu Leu Glu Le - #u Asp Lys Trp Ala Ser                   100      - #           105      - #           110                   - - Leu Trp                                                                    - -  - - (2) INFORMATION FOR SEQ ID NO:7:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 528 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: CDS                                                              (B) LOCATION: 1..528                                                  - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:                                - - GGA GTA GCA CCC ACC AAG GCA AAG AGA AGA GT - #G GTG CAG AGA GAA AAA            48                                                                        Gly Val Ala Pro Thr Lys Ala Lys Arg Arg Va - #l Val Gln Arg Glu Lys              1               5 - #                 10 - #                 15               - - AGA GCA GTG GGA ATA GGA GCT TTG TTC CTT GG - #G TTC TTG GGA GCA GCA            96                                                                        Arg Ala Val Gly Ile Gly Ala Leu Phe Leu Gl - #y Phe Leu Gly Ala Ala                         20     - #             25     - #             30                   - - GGA AGC ACT ATG GGC GCA GCG TCA ATG ACG CT - #G ACG GTA CAG GCC AGA           144                                                                        Gly Ser Thr Met Gly Ala Ala Ser Met Thr Le - #u Thr Val Gln Ala Arg                     35         - #         40         - #         45                       - - CAA TTA TTG TCT GGT ATA GTG CAG CAG CAG AA - #C AAT TTG CTG AGG GCT           192                                                                        Gln Leu Leu Ser Gly Ile Val Gln Gln Gln As - #n Asn Leu Leu Arg Ala                 50             - #     55             - #     60                           - - ATT GAG GCG CAA CAG CAT CTG TTG CAA CTC AC - #A GTC TGG GGC ATC AAG           240                                                                        Ile Glu Ala Gln Gln His Leu Leu Gln Leu Th - #r Val Trp Gly Ile Lys             65                 - # 70                 - # 75                 - # 80        - - CAG CTC CAG GCA AGA ATC CTG GCT GTG GAA AG - #A TAC CTA AAG GAT CAA           288                                                                        Gln Leu Gln Ala Arg Ile Leu Ala Val Glu Ar - #g Tyr Leu Lys Asp Gln                             85 - #                 90 - #                 95               - - CAG CTC CTG GGG ATT TGG GGT TGC TCT GGA AA - #A CTC ATT TGC ACC ACT           336                                                                        Gln Leu Leu Gly Ile Trp Gly Cys Ser Gly Ly - #s Leu Ile Cys Thr Thr                        100      - #           105      - #           110                   - - GCT GTG CCT TGG AAT GCT AGT TGG AGT AAT AA - #A TCT CTG GAA CAG ATT           384                                                                        Ala Val Pro Trp Asn Ala Ser Trp Ser Asn Ly - #s Ser Leu Glu Gln Ile                    115          - #       120          - #       125                       - - TGG AAT AAC ATG ACC TGG ATG GAG TGG GAC AG - #A GAA ATT AAC AAT TAC           432                                                                        Trp Asn Asn Met Thr Trp Met Glu Trp Asp Ar - #g Glu Ile Asn Asn Tyr                130              - #   135              - #   140                           - - ACA AGC TTA ATA CAC TCC TTA ATT GAA GAA TC - #G CAA AAC CAG CAA GAA           480                                                                        Thr Ser Leu Ile His Ser Leu Ile Glu Glu Se - #r Gln Asn Gln Gln Glu            145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - AAG AAT GAA CAA GAA TTA TTG GAA TTA GAT AA - #A TGG GCA AGT TTG         TGG      528                                                                     Lys Asn Glu Gln Glu Leu Leu Glu Leu Asp Ly - #s Trp Ala Ser Leu Trp                           165  - #               170  - #               175               - -  - - (2) INFORMATION FOR SEQ ID NO:8:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 176 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:                                - - Gly Val Ala Pro Thr Lys Ala Lys Arg Arg Va - #l Val Gln Arg Glu Lys         1               5 - #                 10 - #                 15               - - Arg Ala Val Gly Ile Gly Ala Leu Phe Leu Gl - #y Phe Leu Gly Ala Ala                    20     - #             25     - #             30                   - - Gly Ser Thr Met Gly Ala Ala Ser Met Thr Le - #u Thr Val Gln Ala Arg                35         - #         40         - #         45                       - - Gln Leu Leu Ser Gly Ile Val Gln Gln Gln As - #n Asn Leu Leu Arg Ala            50             - #     55             - #     60                           - - Ile Glu Ala Gln Gln His Leu Leu Gln Leu Th - #r Val Trp Gly Ile Lys        65                 - # 70                 - # 75                 - # 80        - - Gln Leu Gln Ala Arg Ile Leu Ala Val Glu Ar - #g Tyr Leu Lys Asp Gln                        85 - #                 90 - #                 95               - - Gln Leu Leu Gly Ile Trp Gly Cys Ser Gly Ly - #s Leu Ile Cys Thr Thr                   100      - #           105      - #           110                   - - Ala Val Pro Trp Asn Ala Ser Trp Ser Asn Ly - #s Ser Leu Glu Gln Ile               115          - #       120          - #       125                       - - Trp Asn Asn Met Thr Trp Met Glu Trp Asp Ar - #g Glu Ile Asn Asn Tyr           130              - #   135              - #   140                           - - Thr Ser Leu Ile His Ser Leu Ile Glu Glu Se - #r Gln Asn Gln Gln Glu       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Lys Asn Glu Gln Glu Leu Leu Glu Leu Asp Ly - #s Trp Ala Ser Leu         Trp                                                                                              165  - #               170  - #               175              - -  - - (2) INFORMATION FOR SEQ ID NO:9:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 47 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:                                - - GATCCATGGG TGCGAGAGCG TCAGTATTAA GCGGGGGAGA ATTAGAT   - #                     47                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO:10:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 45 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:                               - - CGATCTAATT CTCCCCCGCT TAATACTGAC GCTCTCGCAC CCATG   - #                       - #45                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO:11:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 18 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:                               - - GATCTCTAAG GATCCTTA             - #                  - #                       - #  18                                                                    - -  - - (2) INFORMATION FOR SEQ ID NO:12:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 18 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:                               - - GATCTAAGGA TCCTTAGA             - #                  - #                       - #  18                                                                    - -  - - (2) INFORMATION FOR SEQ ID NO:13:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 24 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:                               - - CAGATCTCCG GAGTAGCACC CACC          - #                  - #                     24                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO:14:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 26 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:                               - - GAGATCTGTT AAGCATTCCA AGGCAC          - #                  - #                   26                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO:15:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 30 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15:                               - - CTCGAAGATC TCCAGGGCTA TTGAGGCGCA         - #                  - #                30                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO:16:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 30 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16:                               - - CTCGAAGATC TATTACCACA AACTTGCCCA         - #                  - #                30                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO:17:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 34 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17:                               - - CGCTGATCAA TGAGAGTGHA GGAGAAATAT CAGC       - #                  -       #        34                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO:18:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 34 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18:                               - - CGCTGATCAT TATAGCAAAA TCCTTTCCAA GCCC       - #                  -      #        34                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:19:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 357 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19:                               - - GGAGTAGCAC CCACCAAGGC AAAGAGAAGA GTGGTGCAGA GAGAAAAAAG AG -              #CAGTGGGA     60                                                                  - - ATAGGAGCTT TGTTCCTTGG GTTCTTGGGA GCAGCAGGAA GCACTATGGG CG -             #CAGCGTCA    120                                                                  - - ATGACGCTGA CGGTACAGGC CAGACAATTA TTGTCTGGTA TAGTGCAGCA GC -             #AGAACAAT    180                                                                  - - TTGCTGAGGG CTATTGAGGC GCAACAGCAT CTGTTGCAAC TCACAGTCTG GG -             #GCATCAAG    240                                                                  - - CAGCTCCAGG CAAGAATCCT GGCTGTGGAA AGATACCTAA AGGATCAACA GC -             #TCCTGGGG    300                                                                  - - ATTTGGGGTT GCTCTGGAAA ACTCATTTGC ACCACTGCTG TGCCTTGGAA TG - #CTTAA            357                                                                        - -  - - (2) INFORMATION FOR SEQ ID NO:20:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 345 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20:                               - - AGGGCTATTG AGGCGCAACA GCATCTGTTG CAACTCACAG TCTGGGGCAT CA -              #AGCAGCTC     60                                                                  - - CAGGCAAGAA TCCTGGCTGT GGAAAGATAC CTAAAGGATC AACAGCTCCT GG -             #GGATTTGG    120                                                                  - - GGTTGCTCTG GAAAACTCAT TTGCACCACT GCTGTGCCTT GGAATGCTAG TT -             #GGAGTAAT    180                                                                  - - AAATCTCTGG AACAGATTTG GAATAACATG ACCTGGATGG AGTGGGACAG AG -             #AAATTAAC    240                                                                  - - AATTACACAA GCTTAATACA CTCCTTAATT GAAGAATCGC AAAACCAGCA AG -             #AAAAGAAT    300                                                                  - - GAACAAGAAT TATTGGAATT AGATAAATGG GCAAGTTTGT GGTAA   - #                      345                                                                         - -  - - (2) INFORMATION FOR SEQ ID NO:21:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 531 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21:                               - - GGAGTAGCAC CCACCAAGGC AAAGAGAAGA GTGGTGCAGA GAGAAAAAAG AG -              #CAGTGGGA     60                                                                  - - ATAGGAGCTT TGTTCCTTGG GTTCTTGGGA GCAGCAGGAA GCACTATGGG CG -             #CAGCGTCA    120                                                                  - - ATGACGCTGA CGGTACAGGC CAGACAATTA TTGTCTGGTA TAGTGCAGCA GC -             #AGAACAAT    180                                                                  - - TTGCTGAGGG CTATTGAGGC GCAACAGCAT CTGTTGCAAC TCACAGTCTG GG -             #GCATCAAG    240                                                                  - - CAGCTCCAGG CAAGAATCCT GGCTGTGGAA AGATACCTAA AGGATCAACA GC -             #TCCTGGGG    300                                                                  - - ATTTGGGGTT GCTCTGGAAA ACTCATTTGC ACCACTGCTG TGCCTTGGAA TG -             #CTAGTTGG    360                                                                  - - AGTAATAAAT CTCTGGAACA GATTTGGAAT AACATGACCT GGATGGAGTG GG -             #ACAGAGAA    420                                                                  - - ATTAACAATT ACACAAGCTT AATACACTCC TTAATTGAAG AATCGCAAAA CC -             #AGCAAGAA    480                                                                  - - AAGAATGAAC AAGAATTATT GGAATTAGAT AAATGGGCAA GTTTGTGGTA A - #                 531                                                                       __________________________________________________________________________ 

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
 1. A method for detection of a disease state which comprises utilizing an insoluble form of at least one recombinant protein in a flow cytometric immunofluorescence assay, said method comprising:(i) obtaining a sample of biological fluid within which the disease state is to be detected; (ii) adding a predetermined amount of said insoluble form of at least one recombinant protein to said sample to form a mixture, wherein said insoluble form being produced in particle form by expression in baculovirus or in an expression system producing a particle form, and wherein said insoluble form is the carrier and the antigen; (iii) incubating said mixture for a period of time sufficient to permit association between said insoluble form of at least one recombinant protein and antibodies within said sample to form an incubated mixture; (iv) washing said incubated mixture; (v) adding a labelled antibody to the mixture of step (iv) and incubating for a period of time sufficient for said labeled antibody to bind with antibodies within said incubated mixture to form a labeled mixture; (vi) washing said labeled mixture; (vii) detecting IgM complexes formed in said washed labeled mixture using flow cytometric immunofluorescence; and (viii) correlating detection of IgM complexes with a disease state, wherein an increase level of IgM over the control level is indicative of the disease state.
 2. The method of claim 1 wherein the recombinant protein is expressed in a baculovirus.
 3. The method of claim 1 wherein the disease state is selected from the group consisting of HIV infection, hepatitis and HTLV infection.
 4. The method of claim 3 wherein the disease is selected from the group consisting of HIV-1 infection, HIV-2 infection, hepatitis B infection, hepatitis C infection, HTLV-1 infection and HTLV-2 infection.
 5. The method of claim 4 wherein the disease state is HIV-1 infection.
 6. The method of claim 4 wherein the disease state is hepatitis B infection.
 7. The method of claim 3, wherein the disease state is HIV infection and the said at least one recombinant protein comprises po197, gp160, or a protein comprising SEQ ID NO:2, optionally fused to an amino acid sequence of a selected fusion protein having a sequence selected from the group consisting of SEQ ID NO: 4, SEQ ID NO: 6, and SEQ ID NO: 8; or mixtures thereof, and variants thereof.
 8. The method of claim 7 wherein a mixture of gag-p45, po197 and gp160 is utilized as carrier and antigen.
 9. The method of claim 7, wherein said recombinant protein further comprises an amino acid sequence of SEQ ID NO:4 as the selected fusion partner.
 10. The method of claim 7, wherein said recombinant protein further comprises an amino acid sequence of SEQ ID NO:6 as the selected fusion partner.
 11. The method of claim 7, wherein said recombinant protein further comprises an amino acid sequence of SEQ ID NO:8 as the selected fusion partner.
 12. The method of claim 7, wherein the selected fusion partner has at least one immunoreactive domain. 